People make comprehension easier by predicting upcoming utterances. But what happens when people comprehend and produce utterances concurrently, in two different languages? That is the question addressed in this thesis, which considers the role of prediction in simultaneous and consecutive interpreting. After developing a model of prediction in simultaneous interpreting, the dissertation reports three eye-tracking studies which use a visual-world paradigm. These studies explore whether prediction takes place during simultaneous interpreting; how specific this prediction is; whether interpreters predict differently from other bilinguals; whether training affects prediction; and whether a consecutive interpreting task affects predictive processing. The dissertation concludes that prediction often takes place in both simultaneous and consecutive interpreting, even in noisy conditions, and that interpreters tend to predict earlier and to a greater extent than other bilinguals. Exploratory findings suggest that greater synchronicity of comprehension and production supports prediction – something that could be investigated in future research.